Engine supercharging air cooling system

ABSTRACT

Disclosed is a method and system utilizing two turbochargers (gas driven compressor) for providing compressed air at relatively cool ambient temperature to an internal combustion engine. Interposed between the two turbochargers is an air-to-air intercooler. The first turbocharger is driven by the exhaust gases from the engine to provide compressed heated fresh air to the turbine side of the second turbocharger. The intercooler acts to lower the temperature prior to entrance into the second turbocharger and the remaining heat loss occurs by turbine expansion of this air across the turbine wheel, thus providing cool fresh compressed intake air into the engine. Cooling air for the intercooler is provided by the compressor or fan portion of the second turbocharger combination through the suction of the intake air to that compressor being placed across the intercooler.

United States Patent 11 1 Crook et al.

ENGINE SUPERCHARGING AIR COOLING SYSTEM [75] Inventors: James E. Crook,Speedway; John F.

Cutler, Jr.; Jai K. Khanna, both of Indianapolis, all of Ind.

[73] Assignee: Wallace-Murray Corporation, New

York, NY.

[22] Filed: July 5, 1972 21 Appl. No.: 269,062

52 U.S.Cl ..,..6q 61 2 [51] Int. Cl. F02!) 37/04 [58] Field of Search60/13 [56] References Cited UNITED STATES PATENTS 2,877,622 3/1959Antonissen 60/13 3,141,293 7/1964 Crooks 60/13 2,918,787 12/1959 Schelp60/13 2,703,560 3/1955 Lieberherr... 60/13 2,766,744 10/1956 Steiger60/13 FOREIGN PATENTS OR APPLICATIONS 767,956 2/1957 Great Britain...60/13 743,219 1/1956 Great Britain 60/13 [451 Mar. 12, 1974 PrimaryExaminerCarlton R. Croyle Assistant ExaminerWarren Olsen Attorney,Agent, or FirmCameron, Kerkam, Sutton, Stowell & Stowell 5 7] ABSTRACTinto the second turbocharger and the remaining heat loss occurs byturbine expansion of this air across the turbine wheel, thus providingcool fresh compressed intake air into the engine. Cooling air for theintercooler is provided by the compressor or fan portion of the secondturbocharger combination through the suction of the intake air to thatcompressor being placed across the intercooler.

6 Claims, 1 Drawing Figure ENGINE SUPERCHARGING AIR COOLING SYSTEMBACKGROUND OF THE INVENTION through which passes the high pressure, hightempera- I ture air for charging the engine. The maintenance of maximumoxygen content per unit volume of charging air, as pointed out in theabove mentioned patent, is an important advantage of charged aircooling; however, the more recent concern with reduction of undesirableengine exhaust emissions makes such treatment of the engine charging aira matter of increasing interest for transport and industrial dieselengine users and manufacturers. Lower combustion temperatures, ingeneral, produce lower toxic nitrogen oxide exhaust emissions, and,since cooling the engine charging air provides lower combustiontemperatures, and also provides a more dense air, providing a compactefficient charge air cooling system is a matter of growing urgency andimportance. The concept of utilizing a single turbocharger assembly witha compressor housing divided into two separate collector chambers andthus creating dual flow paths through the compressor component whichpermits drawing cooled, ambient air through an externally located heatexchanger and then into the intake of one compressor flow path whichpermits this air flow to pass in heat exchange relation to the highpressure air output of the other compressor flow path is disclosed inBenisek Patent application Ser. No. 263,009, filed June 15, l972 andassigned to the assignee of the present application. The concept of thepresent invention differs in that two turbocharger combinations areutilized to achieve the two discrete flow paths, including the secondturbocharger which is driven by the compressed air output of the firstturbocharger. This has an advantage in that it permits the firstturbocharger compressor to draw air from the atmosphere and pass thehigh pressure output of the compressor in heat exchange relation withatmospheric cooling air flow, which is being drawn through theintercooler by the second turbocharger compressor or fan. The cooledhigh pressure air is then passed through the turbine component of thesecond turbocharger so that the turbine expansion can remove additionalheat from the compressed air before it enters the intake manifold of theengine. More cooling of the engine charge air is thus achieved and theexternal heat exchanger can be of a minimal size.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a schematicillustration of the turbochargers incorporated into a system utilizingan external heat exchanger and providing for the air charging of aninternal combustion engine DESCRIPTION OF THE PREFERRED EMBODIMENT.

Referring initially to the drawing, there is illustrated an air chargingsystem comprised of four major elements. The first of these elements isa turbocharger generally indicated by the numeral 11. The second ofthese elements is a second turbocharger generally indicated by thenumeral 12. The element 12 is of the same configuration as the firstturbocharger 11, however, it functions as an air turbine coupled withand driving a blower. The third of these elements is an intercoolergenerally designated as 13, interposed between turbochargers 11 and 12.The fourth of the elements is the engine, preferably a diesel engine,generally designated as 14. If desired, an air cleaner may be used inthe system to filter the intake air. In the drawings such a cleaner isgenerally indicated by the numeral 15. Each of the turbochargers, l 1and 12, is of conventional construction such as that disclosed in U.S.Pat. No. 3,090,546 dated May 21, 1963. However, it should be understoodthat other forms of turbine driven fans may be utilized in place ofturbocharger l2. Turbocharger 11, for example, includes a turbinehousing 20 enclosing a conventional bladed turbine wheel (not shown).The turbine housing 20 is provided with a flanged inlet passage 24 whichtransmits engine exhaust gases emitted from the exhaust manifold 40 ofengine 14 to the turbine wheel. The turbine component itself is ofconventional construction.

Connected to the turbine wheel by a shaft (not shown) is a compressorwheel (not shown) which is contained within a compressor housing 26.High pressure and high temperature gases, entering the turbine housing20 are expanded through the turbine wheel, causing the shaft andcompressor wheel to rotate at high speed. The spent gases are dischargedthrough a turbine outlet passage 25. As the compressor wheel is rotatedat high speeds it will draw air through the inlet passage 27, compressthe air and discharge it through the outlet passage 28. If necessary,the intake air may previously have been drawn through the air cleaner15. The air discharged through the outlet passage 28 is then directed toone side of an air-to-air intercooler 13 through which it is passed forcooling purposes to an inlet passage 32 in a turbine housing 30. The airas it is directed into the turbine housing 30 causes the turbine wheel(not shown) in this turbine housing to rotate at high speed as a resultof the expansion of the air. The air is then discharged through theturbine outlet passage 34. At this stage the air is directed to theintake 42-of the engine 14.

The turbine 30 through a shaft (not shown) drives a compressor wheel orfan contained within a housing 35 which has an outlet 36 directed toatmosphere. Thus, as the turbine 30 is operating because of the passageof air through its housing, the compressor 35 is operatingsimultaneously to draw cooling air through the intercooler and into aninlet 37 of the housing 35.

Beginning at the engine 14, the operation of the system is initiated bythe exhaust gases which are emitted from the exhaust manifold 40 anddischarged into the inlet 24 of turbine housing 20 wherein turbineexpansion occurs prior to the discharge of the gases to an exhaustsystem and atmosphere through the outlet 25. Inasmuch as it has beenfound that to operate effectively and economically diesel engines of thetype involved here (approximately 200 psi BMEP) should receivesupercharged air at their rated speeds and loads at a maximum pressureratio of approximately 3.0 with a minimum ratio of approximately 2.0;and inasmuch as the pressure ratio of the compressed air generated bythe first turbocharger should not exceed 4.5, otherwise too muchbackpressure will be imposed on the engine, of

this power level, and should not be less than 3.2 or insufficient airwill be charged to the engine, the desired discharge air pressure ratioof the first turbocharger in this system has been determined to beapproximately 3.7. As previously indicated, the operation of the turbine20 causes a compressor 26 to be operated which draws ambient air throughan inlet 27 to compress that air and discharge it through the outlet 28at the desired pressureratio of 3.7 and an increased temperature as aresult of compression ranging from 400 to 500F.

For greater cleanliness and long life of the engine this intake air maybe drawn through an air cleaner prior to its induction through the inlet27. From the outlet 28 the higher pressure, higher temperature air ispassed through an air-to-air intercooler generally illustrated at 13from which it is discharged at an approximate temperature of 180 whilestill maintaining its 3.7 pressure ratio. This air is then passed intoan inlet 32 of a turbine housing 30 to drive a turbine wheel (not shown)SO that turbine expansion will occur and the air will then be dischargedat a desired approximate pressure ratio of 2.5 and a desired temperatureof approximately 100F. From the discharge outlet 34 the air is thendirected into the intake manifold 42 of the engine 14.

When the turbine 30 is operating it in turn causes a compressor wheel orfan contained in housing 35 of the second turbocharger to turn at highspeeds which thereby creates a suction at the inlet opening 37 whichcauses additional air to be drawn through the optional air cleaner 15and through the air-to-air intercooler 13 before it is discharged toatmopshere through the outlet 36. The air movement created by thissecond air compressor or fan is the cooling air for the intercooler.

The merits of this system thus become obvious that the engine receivesintake air at a normally accepted maximum pressure for such engines(approximately 200 psi BMEP) of approximately a 2.5 pressure ratio at amuch lower temperature than has previously been delivered to such anengine unless extensive external cooling means were utilized.

We claim:

l. A supercharging system for an internal combustion engine having atleast one air intake manifold and at least one exhaust manifold,including a first turbocharger comprising a first compressor componentand a first turbine component being operatively connected through aninlet to said at least one exhaust manifold to receive exhaust gases foroperating said first turbine component, said first turbine componentbeing in driv-.

ing relationship to said first compressor component, said firstcompressor component being operatively connected to transmit compressedair from a discharge opening through an intermediate intercooler to asecond turbine component, said second turbine component being in drivingrelationship to a second compressor component, an inlet in said secondcompressor component connected to said intermediate intercoolerfordrawing ambient cooling air through said intercooler to cool saidcompressed air as it passes through said intercooler and into saidsecond turbine component, means for transmitting air discharged fromsaid second turbine component to said at least one air intake manifold,said second compressor discharging to ambient.

2. A system as called for in claim 1 wherein at least one air cleaner isinstalled to clean air to be drawn into said first compressor componentand air to be drawn through said intercooler and into said secondcompressor component.

3. In a supercharger system for an internal combustion engine, a firstturbocharger, having a turbine and a compressor, and a secondturbocharger, having a turbine and a compressor, an air-to-airintercooler interposed between the first turbocharger compressor and thesecond turbocharger turbine, means for transmitting engine exhaust gasfrom said engine to the turbine of said first turbocharger, thecompressor of said first turbocharger compressing ambient air anddischarging said air at a first pressure ratio ranging from 3.2 to 4.5and at a first temperature ranging from 400 to 500F, means fortransmitting said compressed air from said first turbocharger compressorthrough said intercooler to supply said air to the turbine of saidsecond turbocharger at a second temperature of approximately 40% of saidfirst temperature, said second turbine in said second turbochargerexpanding said air to a final pres-- sure ratio and final temperatureconsiderably lower than said first pressure ratio and said secondtemperature, and at least double atmospheric pressure, and means fordelivering said air at said final pressure ratio and said finaltemperature to said engine, said second turbocharger compressor drawingambient air into said intercooler and discharging to ambient.

4. In a system as called for in claim 3, air cleaning means for cleaningambient air brought into said system.

5. A system as called for in claim 4 wherein said first pressure ratiois approximately 3.7 and said second temperature is approximately 180C.

6. A system as called for in claim 5 wherein said final pressure ratiois approximately 2.5 and said final temperature is approximately F.

, s aa t r

1. A supercharging system for an internal combustion engine having atleast one air intake manifold and at least one exhaust manifold,including a first turbocharger comprising a first compressor componentand a first turbine component being operatively connected through aninlet to said at least one exhaust manifold to receive exhaust gases foroperating said first turbine component, said first turbine componentbeing in driving relationship to said first compressor component, saidfirst compressor component being operatively connected to transmitcompressed air from a discharge opening through an intermediateintercooler to a second turbine component, said second turbine componentbeing in driving relationship to a second compressor component, an inletin said second compressor component connected to said intermediateintercooler for drawing ambient cooling air through said intercooler tocool said compressed air as it passes through said intercooler and intosaid second turbine component, means for transmitting air dischargedfrom said second turbine component to said at least one air intakemanifold, said second compressor discharging to ambient.
 2. A system ascalled for in claim 1 wherein at least one air cleaner is installed toclean air to be drawn into said first compressor component and air to bedrawn through said intercooler and into said second compressorcomponent.
 3. In a sUpercharger system for an internal combustionengine, a first turbocharger, having a turbine and a compressor, and asecond turbocharger, having a turbine and a compressor, an air-to-airintercooler interposed between the first turbocharger compressor and thesecond turbocharger turbine, means for transmitting engine exhaust gasfrom said engine to the turbine of said first turbocharger, thecompressor of said first turbocharger compressing ambient air anddischarging said air at a first pressure ratio ranging from 3.2 to 4.5and at a first temperature ranging from 400* to 500*F, means fortransmitting said compressed air from said first turbocharger compressorthrough said intercooler to supply said air to the turbine of saidsecond turbocharger at a second temperature of approximately 40% of saidfirst temperature, said second turbine in said second turbochargerexpanding said air to a final pressure ratio and final temperatureconsiderably lower than said first pressure ratio and said secondtemperature, and at least double atmospheric pressure, and means fordelivering said air at said final pressure ratio and said finaltemperature to said engine, said second turbocharger compressor drawingambient air into said intercooler and discharging to ambient.
 4. In asystem as called for in claim 3, air cleaning means for cleaning ambientair brought into said system.
 5. A system as called for in claim 4wherein said first pressure ratio is approximately 3.7 and said secondtemperature is approximately 180*C.
 6. A system as called for in claim 5wherein said final pressure ratio is approximately 2.5 and said finaltemperature is approximately 100*F.